<template>
    <el-breadcrumb class="app-breadcrumb" separator="/">
        <transition-group name="breadcrumb">
            <el-breadcrumb-item v-for="(item,index) in levelList" :key="item.path">
                <span v-if="item.redirect==='noRedirect'||index==levelList.length-1"
                    class="no-redirect">{{ item.meta.title }}</span>
                <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
            </el-breadcrumb-item>
        </transition-group>
    </el-breadcrumb>
</template>

<script>
    import pathToRegexp from 'path-to-regexp'

    export default {
        name: 'app-Breadcrumb',
        data() {
            return {
                levelList: null
            }
        },
        watch: {
            $route(route) {
                // if you go to the redirect page, do not update the breadcrumbs
                if (route.path.startsWith('/redirect/')) {
                    return
                }
                this.getBreadcrumb()
            }
        },
        created() {
            this.getBreadcrumb()
        },
        methods: {
            getBreadcrumb() {
                // only show routes with meta.title
                let matched = this.$route.matched.filter(item => item.meta && item.meta.title)
                const first = matched[0]

                if (!this.isDashboard(first)) {
                    matched = [{
                        path: '/guide',
                        meta: {
                            title: '首页'
                        }
                    }].concat(matched)
                }

                this.levelList = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false)
            },
            isDashboard(route) {
                const name = route && route.name
                if (!name) {
                    return false
                }
                // return name.trim().toLocaleLowerCase() === '首页'.toLocaleLowerCase()
                return name === 'appGuide'
            },
            pathCompile(path) {
                // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
                const {
                    params
                } = this.$route
                var toPath = pathToRegexp.compile(path)

                return toPath(params)
            },
            handleLink(item) {
                const {
                    redirect,
                    path
                } = item
                if (redirect) {
                    this.$router.push(redirect)
                    return
                }

                if (path !== '/guide') {
                    this.$router.push(this.pathCompile(path))
                } else {
                    this.$router.push('/guide')
                }

            }
        }
    }
</script>

<style lang="scss" scoped>
    .app-breadcrumb.el-breadcrumb {
        display: inline-block;
        font-size: 14px;
        line-height: 50px;
        margin-left: 8px;

        .no-redirect {
            color: #97a8be;
            cursor: text;
        }
    }
</style>